Two bidentate NS ligands were synthesized by the condensation reaction of S-2-methylbenzyldithiocarbazate (S2MBDTC) with 2-methoxybenzaldehyde (2MB) and 3-methoxybenzaldehyde (3MB). The ligands were reacted separately with acetates of Cu(II), Ni(II) and Zn(II) yielding 1:2 (metal:ligand) complexes. The metal complexes formed were expected to have a general formula of [M(NS)₂] where M = Cu²⁺, Ni²⁺, and Zn²⁺. These compounds were characterized by elemental analysis, molar conductivity, magnetic susceptibility and various spectroscopic techniques. The magnetic susceptibility measurements and spectral results supported the predicted coordination geometry in which the Schiff bases behaved as bidentate NS donor ligands coordinating via the azomethine nitrogen and thiolate sulfur. The molecular structures of the isomeric S2M2MBH (1) and S2M3MBH (2) were established by X-ray crystallography to have very similar l-shaped structures. The Schiff bases and their metal complexes were evaluated for their biological activities against estrogen receptor-positive (MCF-7) and estrogen receptor-negative (MDA-MB-231) breast cancer cell lines. Only the Cu(II) complexes showed marked cytotoxicity against the cancer cell lines. Both Schiff bases and other metal complexes were found to be inactive. In concordance with the cytotoxicity studies, the DNA binding studies indicated that Cu(II) complexes have a strong DNA binding affinity.

A series of Schiff bases have been successfully synthesized through the acid-catalyzed condensation of S-substituted dithiocarbazates and three enantiomerically pure monoterpenes, (1 R )-(+)-camphor, (1 S )-(-)-camphor, (1 R )-(-)-camphorquinone, (1 S )-(+)-camphorquinone, ( R )-(-)-carvone and ( S )-(+)-carvone. Spectroscopic results revealed that the Schiff bases containing camphor or carvone likely adopted an E -configuration along the characteristic imine bond while those containing camphorquinone assumed a Z -configuration. The antidengue potential of these compounds was evaluated based on DENV 2 caused cytopathic effect (CPE) reduction-based in vitro evaluation. The compounds were validated through secondary foci forming unit reduction assay (FFURA). Compounds were also tested for their cytotoxicity against Vero cells. The compounds showed variable degrees of antiviral activity with the camphor compounds displaying the highest antidengue potential. The enantiomers of the compounds behaved almost similarly during the antiviral evaluation.

The title Zn^IIcomplex, [Zn(C₁₈H₁₈N₃S)₂], (I), features two independent but chemically equivalent molecules in the asymmetric unit. In each, the thiosemicarbazonate monoanion coordinates the Zn^IIatomviathe thiolate-S and imine-N atoms, with the resulting N₂S₂donor set defining a distorted tetrahedral geometry. The five-membered ZnSCN₂chelate rings adopt distinct conformations in each independent molecule,i.e.one ring is almost planar while the other is twisted about the Zn—S bond. In the crystal, the two molecules comprising the asymmetric unit are linked by amine-N—H...N(imine) and amine-N—H...S(thiolate) hydrogen bondsviaan eight-membered heterosynthon, {...HNCN...HNCS}. The dimeric aggregates are further consolidated by benzene-C—H...S(thiolate) interactions and are linked into a zigzag supramolecular chain along thecaxisviaamine-N—H...S(thiolate) hydrogen bonds. The chains are connected into a three-dimensional architectureviaphenyl-C—H...π(phenyl) and π–π interactions, the latter occurring between chelate and phenyl rings [inter-centroid separation = 3.6873 (11) Å]. The analysis of the Hirshfeld surfaces calculated for (I) emphasizes the different interactions formed by the independent molecules in the crystal and the impact of the π–π interactions between chelate and phenyl rings.

Two independent mol-ecules comprise the asymmetric unit of the title compound, C(13)H(19)N(3)OS, which differ in the conformations of the residues linking the thio-urea and the terminal benzene ring, as manifested in the C(m)-C(m)-C(a)-C(a) torsion angles [78.03 (16) and -93.64 (16)°, respectively; m = methyl-ene and a = aromatic]. The dihedral angles [84.40 (4) and 88.28 (5)°] formed between the thio-urea residue and the benzene ring indicate an almost orthogonal relationship. In each thio-urea residue, the N-H hydrogen atoms are anti, and the terminal N-H hydrogen atom forms an intra-molecular N-H⋯N hydrogen bond with the imine-N atom. In each case, the conformation about the imine C=N double bond [1.2812 (17) and 1.2801 (17) Å] is E. In the crystal, the mol-ecules are connected by N-H⋯S hydrogen bonds and these are connected into four mol-ecule aggregates via N-H⋯O hydrogen bonds, which are assembled into a two-dimensional array parallel to (011) via C-H⋯π and π-π inter-actions [ring centroid-centroid distance = 3.8344 (9) Å].